Doppler mirror image artifacts mimicking mitral regurgitation in patients with mechanical bileaflet mitral valve prostheses.

Abstract

To characterize the origin and mechanisms of generation of Doppler mirror images in the left atrium observed in patients with mechanical bileaflet mitral valve prosthesis. We hypothesized that these systolic colour Doppler images are artifactual and generated by reflection of the left ventricular outflow tract flow at the leaflet of the mitral valve prosthesis. Fifty patients with mechanical bileaflet mitral valves were prospectively examined by means of transthoracic Doppler-echocardiography. From different apical views, the left atrium was carefully interrogated for systolic colour flow signals, which were further analysed by pulsed wave Doppler. In all patients, a systolic colour Doppler signal was detected in the left atrium. Pulsed wave Doppler analysis revealed a low velocity signal (= mirror image) corresponding to the shape and duration of the left ventricular outflow tract signal. The peak velocities of these mirror images, however, were consistently lower than the velocities obtained from the left ventricular outflow tract. In addition, if paravalvular mitral valve leakage was present, a high velocity signal identical to the duration of mitral regurgitation time was detected outside the ring of the prosthesis. Mirror image artifacts mimicking mitral regurgitation occur in patients with mechanical mitral valves prosthesis. As mirror image artifacts can be specifically identified by analysis of shape. velocity, and duration of pulsed wave Doppler spectra, their identification will help to avoid misinterpretation of both spectral and colour Doppler signals in patients with prosthetic mitral valves.